About 80%‐85% of lung cancers are non–small‐cell lung cancer.2 Neuron‐specific enolase (NSE) is an important tumor marker in the serum of patients with lung cancer.3, 4, 5 Elevated serum NSE levels are also associated with neuroblastoma, neuroendocrine neoplasms, renal cell carcinoma, multiple myeloma, brain trauma, Guillain‐Barre syndrome, and other diseases.6, 7, 8, 9 Therefore, measurement of serum NSE can be used as an auxiliary marker for the diagnosis of several diseases. The gene discussed is ENO2; the disease is brain injury.